Articles | Volume 10, issue 19
Atmos. Chem. Phys., 10, 9451–9472, 2010
Atmos. Chem. Phys., 10, 9451–9472, 2010

  07 Oct 2010

07 Oct 2010

Multi-model assessment of stratospheric ozone return dates and ozone recovery in CCMVal-2 models

V. Eyring1, I. Cionni1, G. E. Bodeker2, A. J. Charlton-Perez3, D. E. Kinnison4, J. F. Scinocca5, D. W. Waugh6, H. Akiyoshi7, S. Bekki8, M. P. Chipperfield9, M. Dameris1, S. Dhomse9, S. M. Frith10, H. Garny1, A. Gettelman4, A. Kubin11, U. Langematz11, E. Mancini12, M. Marchand8, T. Nakamura7, L. D. Oman6,13, S. Pawson13, G. Pitari12, D. A. Plummer5, E. Rozanov14,15, T. G. Shepherd16, K. Shibata17, W. Tian9, P. Braesicke18, S. C. Hardiman19, J. F. Lamarque4, O. Morgenstern18,20, J. A. Pyle18, D. Smale20, and Y. Yamashita7,21 V. Eyring et al.
  • 1Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
  • 2Bodeker Scientific, Alexandra, New Zealand
  • 3University of Reading, Department of Meteorology, Reading, UK
  • 4National Center for Atmospheric Research, Boulder, CO, USA
  • 5Environment Canada, Victoria, BC, Canada
  • 6Johns Hopkins University, Department of Earth and Planetary Sciences, Baltimore, Maryland, USA
  • 7National Institute for Environmental Studies, Tsukuba, Japan
  • 8Service d'Aeronomie, Institut Pierre-Simone Laplace, Paris, France
  • 9Institute for Climate and Atmospheric Science, University of Leeds, UK
  • 10Science Systems and Applications, Inc., Lanham MD 20706, USA
  • 11Freie Universität Berlin, Institut für Meteorologie, Berlin, Germany
  • 12Università L'Aquila, Dipartimento di Fisica, L'Aquila, Italy
  • 13NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
  • 14Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center, Davos, Switzerland
  • 15Institute for Atmospheric and Climate Science ETH, Zurich, Switzerland
  • 16University of Toronto, Department of Physics, Canada
  • 17Meteorological Research Institute, Tsukuba, Japan
  • 18University of Cambridge, Department of Chemistry, Cambridge, UK
  • 19Met Office, Exeter, UK
  • 20National Institute of Water and Atmospheric Research, Lauder, New Zealand
  • 21Center for Climate System Research, University of Tokyo, Japan

Abstract. Projections of stratospheric ozone from a suite of chemistry-climate models (CCMs) have been analyzed. In addition to a reference simulation where anthropogenic halogenated ozone depleting substances (ODSs) and greenhouse gases (GHGs) vary with time, sensitivity simulations with either ODS or GHG concentrations fixed at 1960 levels were performed to disaggregate the drivers of projected ozone changes. These simulations were also used to assess the two distinct milestones of ozone returning to historical values (ozone return dates) and ozone no longer being influenced by ODSs (full ozone recovery). The date of ozone returning to historical values does not indicate complete recovery from ODSs in most cases, because GHG-induced changes accelerate or decelerate ozone changes in many regions. In the upper stratosphere where CO2-induced stratospheric cooling increases ozone, full ozone recovery is projected to not likely have occurred by 2100 even though ozone returns to its 1980 or even 1960 levels well before (~2025 and 2040, respectively). In contrast, in the tropical lower stratosphere ozone decreases continuously from 1960 to 2100 due to projected increases in tropical upwelling, while by around 2040 it is already very likely that full recovery from the effects of ODSs has occurred, although ODS concentrations are still elevated by this date. In the midlatitude lower stratosphere the evolution differs from that in the tropics, and rather than a steady decrease in ozone, first a decrease in ozone is simulated from 1960 to 2000, which is then followed by a steady increase through the 21st century. Ozone in the midlatitude lower stratosphere returns to 1980 levels by ~2045 in the Northern Hemisphere (NH) and by ~2055 in the Southern Hemisphere (SH), and full ozone recovery is likely reached by 2100 in both hemispheres. Overall, in all regions except the tropical lower stratosphere, full ozone recovery from ODSs occurs significantly later than the return of total column ozone to its 1980 level. The latest return of total column ozone is projected to occur over Antarctica (~2045–2060) whereas it is not likely that full ozone recovery is reached by the end of the 21st century in this region. Arctic total column ozone is projected to return to 1980 levels well before polar stratospheric halogen loading does so (~2025–2030 for total column ozone, cf. 2050–2070 for Cly+60×Bry) and it is likely that full recovery of total column ozone from the effects of ODSs has occurred by ~2035. In contrast to the Antarctic, by 2100 Arctic total column ozone is projected to be above 1960 levels, but not in the fixed GHG simulation, indicating that climate change plays a significant role.

Final-revised paper